Exactly! It's also useful to have a second (calibrated) counter to compare
results.
I just found out 10 CPM = 100nS/hr. I hope that's correct. I'll modify the
Arduino
code to send Weather packets using Bob's new format in nS/hr .
Note: I don't want to use the Radiation Hazard icon for a metering station
(unless there is
a real and proven hazard condition at that station's location). I know I
proposed a Nuke icon
to Bob last week, but I don't think it's a good idea to use it anymore...
Disclaimer: the data should be used for experimental purposes ONLY! Trying
to interpret
data gathered by amateur meters should be avoided. That being said, if
there is a sudden
trend going up for a long period of time, always check with official sources
like the EPA
in the US first! Anyways regular counters will not detect tiny changes
like fallouts from
Japan unless the situation gets much worse.
Bernard KI6TSF
On Wed, Mar 23, 2011 at 1:33 PM, Julian, G4ILO <julian.g4ilo at gmail.com>wrote:
> The hand held consumer devices with LCD emit a click or beep whenever
> a particle is counted (according to the reviews). So presumably you
> could tap into the signal from the speaker then count the clicks using
> a PIC circuit similar to yours? The LCD reading would be useful to
> validate that your averaging calculation is working correctly.
>> Julian, G4ILO
> G4ILO's Shack: www.g4ilo.com
>>>>>>>>> On 23 March 2011 17:55, Bernard Van Haecke <bernard.vanhaecke at gmail.com>
> wrote:
> > Hi,
> > All Geiger counters work on the same principle. When a particle enters
> the
> > tube it
> > ionises the gas and generates a spike. Counting spikes per minute
> > determines the radioactivity rate in CPM and that's what you want to
> report.
> > The APRS telemetry code I posted on my QRZ page for the Arduino and
> > RadioShield
> > can count the spikes per minute via a digital pin (just make sure you
> don't
> > put 1,000
> > volts into your Arduino) as well as readings from the serial port.
> > Theoretically, any Geiger counter can be used/modified to get the pulse
> > signal and shape
> > it as a TTL 5v pulse. In normal circumstances, you should get between 10
> > and 40 CPM.
> > There is nothing available out of the box so in any case some
> > hacking/testing/experimenting
> > is required. Using a counter with serial port is easier though. Note
> that
> > even those don't
> > report average counts per minute over their serial ports. They report
> > instant counts.
> > I doubt any existing weather station is capable of doing simple maths
> like
> > rolling window
> > averages etc... so there again some hacking is required. The Arduino
> seems
> > to be
> > the easiest way to go (in my opinion).
> > As time goes by I expect hams to come up with simple designs/schematics
> > showing
> > how to hook up a Geiger tube or hack existing counters to connect to
> > Arduinos and
> > the like. Some over here are actually looking into this already.
> > Bernard KI6TSF
> >
> > On Wed, Mar 23, 2011 at 9:07 AM, Julian, G4ILO <julian.g4ilo at gmail.com>
> > wrote:
> >>
> >> A lot of domestic hand-held radiation monitors such as are
> >> manufactured in Ukraine have only an LCD readout. They are much
> >> cheaper than the ones with computer interface. Is there any way that
> >> they could be used? Could the system accommodate manually entered
> >> readings?
> >>
> >> Julian, G4ILO
> >> G4ILO's Shack: www.g4ilo.com
> >>
> >> _______________________________________________
> >> aprssig mailing list
> >> aprssig at tapr.org> >> https://www.tapr.org/cgi-bin/mailman/listinfo/aprssig> >
> >
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